1. Field of the Invention
The present invention relates to a recording apparatus having the function of, for example, a facsimile, copying machine or printer, and a recording apparatus used as an output device for a composite machine having such functions or a work station.
2. Related Background Art
Non-impact recording methods have recently been noticed for the reason that the noise generated in the recording operation is so low as to be negligible. Among them, an ink jet recording method which permits a high speed recording and which can record an image on a so-called plain paper is extremely effective.
In the ink jet recording apparatus, when a recording liquid (ink) is discharged on a recording paper, the ink is often discharged on a recording paper conveying belt due to the malfunction of a paper feeding system, so that the ink is adhered to the conveying belt. Consequently, when the next recording operation is performed, the back surface of the recording paper is smeared by the ink adhered to the conveying belt. To avoid this, it is required for providing a cleaning device for cleaning the conveying belt.
An example of an ink jet recording apparatus having such cleaning device is shown in FIG. 13.
As shown, each of ink jet heads 1C, 1M, 1Y and 1BK is provided at its lower surface with ink discharge nozzles and faces a conveying belt 101 for conveying a recording paper. A conveying belt cleaner is disposed at a paper ejecting area at a downstream side of a driving roller 102 and comprises a liquid absorbing member 119 and a case 120.
The conveying belt 101 is provided with an opening for exhausting ink to outside. The cleaning of the conveying belt 101 is performed at the same time as the recording operation. The liquid absorbing member 119 acting as an ink absorber is always abutted against the belt 101 so that, during the rotation of the belt 101, the latter is always being cleaned by the liquid absorbing member 119.
In FIG. 13, the reference numeral 301 denotes a scanner portion; 302 denotes a printer portion; 303 denotes a paper supply portion; 304 denotes a belt conveying portion; 305 denotes a recording head portion; 306 denotes a recovery cap portion; and 307 denotes a fixing and ejecting portion. Since the liquid absorbing member of the cleaner is required to have the anti-wear feature, it must be made of material having both the ink absorbing feature and the anti-wear feature, with the result that the cleaner becomes expensive. Further, since the material having the best ink absorbing ability cannot be used in the cleaner, the cleaning efficiency for the belt was not satisfactory.
An image forming apparatus such as a copying machine, printer and the like, which has been widely known, is so designed that the recording paper is fed from a paper supply portion such as a cassette and is conveyed to an ejecting portion through an image forming portion. In this case, the recording paper must be always controlled at a given timing from the supply thereof to the ejection thereof. Particularly, since the timing from the supply of the recording paper to the image formation thereon relates to a position of the image recorded on the recording paper, the accurate conveyance of the recording paper is requested. Further, if the conveying speed of the recording paper during the image formation is not constant, the discrepancy in the magnification of the image occurs, with the result that the image will be enlarged or contracted. In particular, in an image forming apparatus having a plurality of image forming portions arranged side by side, the discrepancy between the images recorded at various recording portions will occur. This causes the discrepancy in colors and/or unevenness in color in a color image recording apparatus, thus affecting a bad influence upon the formation of the color image. To prevent such inconvenience, the conveying speed of the recording paper must be constant by accurately transmitting the conveying force from a conveying means to the recording paper.